Effects of ecological disturbance on parasite communities in both people and mantled howler monkeys (Alouatta palliata aequatorialis) living in Ecuador.

摘要

Understanding the relationship between anthropogenic disturbances and wildlife gastrointestinal parasite communities is important to both human health and conservation efforts. Forest logging and fragmentation, burgeoning human population growth, wildlife extraction, and expansion of livestock into formerly undisturbed landscapes can affect and compound the transmission of various pathogens between wildlife and people. This study therefore aims to further understand the relationship between two types of anthropogenic disturbance (forest degradation and human encroachment), and gastrointestinal parasite communities in both humans and mantled howler monkeys, Alouatta palliata aequatorialis by addressing the following: 1) chronicle primate parasitism, 2) investigate association of environmental degradation and parasitism, and 3) assess human attributes and actions associated with parasitism and potential transmission between human and howler monkey populations. Human and monkey endoparasite communities were characterized using morphological and genetic analyses, and people from surrounding communities were administered demographic surveys to evaluate risk factors associated with parasitism. Of 96 howler monkey fecal samples collected, 2 species of apicomplexan, 6 other protozoa, 4 nematodes, and 1 platyhelminth were detected. Four congeners were found in howlers and people: Entamoeba sp., Balantidium sp., Blastocystis sp., and Strongyloides spp. Several key parasites were non-randomly distributed throughout the sampled population. Proximity of agricultural plots and a local biological research station were both associated with the presence of Strongyloides spp. Individuals were more than four times likely to harbor Strongyloides spp. if they lived in areas considered disturbed forest. Individuals infected with Controrchis sp. were found further from human settlements than uninfected individuals and nearly ten times more likely to be found in primary forest. No evidence of shared Blastocystis subtypes were found between howlers and people, though Capillaria sequence types were similar, suggesting either zoonotic transmission or a common source. Several significant human factors were associated with parasite communities. The results from this study support the hypothesis that anthropogenic disturbances can place both primate populations and humans at risk of select gastrointestinal parasites. Aside from the various direct impacts of anthropogenic disturbances, additional focus should be placed on the indirect effects changing ecological systems have on parasite communities in threatened hosts.